I just picked up a used Apple G5 iMac (2005 model) that has a combination analog/optical digital audio output port. The output on the iMac is a mini plug. I want to use it to digitally connect to a Panasonic receiver and I can use either an optical Toslink and S/DIF RCAs input. I can't find a cable that does what I want. Anybody know how to connect this setup?

Pretty sure it's one of those Apple-only, proprietary do-hickeys, as only brought to you by the wonderful world of Apple. In short, check the Apple store and expect to pay way too much... Why Apple can't make use of the same connectivity as the rest of the world never ceases to infuriate, but that seems to be the way it goes.

Some standard toslink cables come with the adapter to fit the headphone output. Mine did. It's just a small piece of plastic that looks like a headphone jack on one end and accepts the toslink on the other.

there are quite a few cables out there that you can use. depending on quality, you can get them from apple, monster, and ixos. the mini adapter can be purchased from fry's, radio shack, echo audio, and others. i purchased a few from fry's for $2.98.

As others have said, neither the analog nor the optical output on the G5 uses a proprietary cable. You can use either a 3.5mm stereo plug for analog output or a mini-Toslink to Toslink for digital.

If your question is which one is preferable, it's likely that the digital to analog converter in your receiver is better than the one in your iMac so that's likely your best option. The cables are inexpensive, though, and it would be easy to compare. A good source for well-made cables at great prices is monoprice.com.

My system works well with the Toslink to mini-Toslink cable set-up. I had a custom length made to fit my needs. There are several companies that will do that for you. If you want to go dirt cheap just get the Toslink cable of choice and slip on one of those little adapters (mini) to one end. I think you can by them for $1 - $2.